The project is designed to study microangiopathy retrospectively from sequential sections of decalcified temporal bones of diabetic patients and their age matched controls using light microscopic and appropriate histochemical technics. Effects of age of onset, duration of diabetes and endocrine status will be correlated with the morphology. Prospective studies are being undertaken utilizing a) surgical specimens of epithelium and the subjacent connective tissue and/or b) temporal bones obtained at autopsy to study the basement membrane thickness of the capillaries of the middle and inner ear.